Various clamping devices have been provided for immovably securing a workpiece or workpieces with respect to a stationary support during a machining and/or welding operation. Most of these devices have incorporated fluid operated actuators, such as hydraulic or pneumatic operated piston and cylinder actuators. While these devices are satisfactory for clamping workpieces to a stationary support, difficulties arise in using clamps of this configuration for use in non-stationary support situations, such as moving transfer devices, conveyors, shuttles or the like. In addition, the use of hydraulic fluid in non-stationary applications can be the source of hydraulic fluid leaks, while the use of pneumatic actuators increases cost of operation by requiring the production of sufficient quantities of compressed air of predefined quality for operating clamping devices. Compressed air generally requires the use of fixed or flexible conduits to communicate the compressed air with the actuator, and may produce compressed air leaks increasing operating costs. Furthermore, it is difficult to obtain a harmonic motion clamp action with a hydraulic or pneumatic actuator, sometimes referred to as a "soft-touch" clamp, where the clamp decelerates adjacent the clamped and/or released position thereby eliminating the need for "bumpers" or other shock absorbing elements. Typically, hydraulic and pneumatic actuated clamps require complex control mechanisms to adjust the rate of actuation of the clamp to eliminate or reduce the amount of shock absorbed as the clamp reaches the clamped position and/or the released position.